1. Field of the Invention
The present invention relates to a positional relationship between a semiconductor device (e.g., a TCP) and a heat sink on a printed circuit board, and a BGA package.
2. Description of the Related Art
Conventionally, when a TCP (tape carrier package) with a high power consumption is mounted on a printed circuit board, a heat sink is required to diffuse heat generated by this TCP.
FIGS. 157 and 158 show a semiconductor device using a conventional printed circuit board. FIG. 158 is a sectional view along the line CLVIII--CLVIII in FIG. 157.
The structure of this semiconductor device will be described.
A printed circuit board 101 comprises an insulating board 11 and wiring patterns 12 formed on the insulating board 11.
A TCP 102 and a heat sink 103 are mounted on the printed circuit board 101.
The TCP 102 comprises a TAB (Tape Automated Bonding) tape constituted by a polyimide tape 13 and leads 14, and a semiconductor chip 15 connected to one end of each of the leads 14.
The other end of each lead 14 of the TCP 102 is connected to the corresponding wiring pattern 12 of the printed circuit board 101 by a solder or the like.
The heat sink 103 consists of a metal such as aluminum, and has a fin-like shape.
The bottom portion of the heat sink 103 is adhered on a surface of the semiconductor chip 15 opposite to an element formation surface thereof with an adhesive or the like.
In the semiconductor device in FIGS. 157 and 158, the heat sink is directly mounted on the semiconductor chip 15 of the TCP 102.
Recently, in order to efficiently dissipate heat generated by the semiconductor chip 15, the size of the heat sink 103 has been increased. For this reason, it is difficult for the leads 14 of the TCP 102 to support the mass of the heat sink 103.
Therefore, no lead 14 has a strength with which it can bear a vibration test of the TCP, and if the heat sink 103 is forcibly mounted, the TCP 102 itself is undesirably damaged.
The present invention has been made to eliminate such a drawback, and has as its object to efficiently diffuse heat generated by a semiconductor device without damaging the semiconductor element (e.g., a TCP) mounted on a printed circuit board.